In general, a heat exchanger is a part used in a heat-exchanging cycle. The heat exchanger may serve as a condenser or evaporator to heat-exchange a refrigerant flowing therein with an external fluid.
The heat exchanger may be largely classified into a fin-and-tube type and a micro channel type according to a shape thereof. The fin-and-tube type heat exchanger includes a plurality of fins and a tube having a circular shape or a shape similar to that circular shape and passing through the fins. The micro channel type heat exchanger includes a plurality of flat tubes through which a refrigerant flows and a fin disposed between the plurality of flat tubes. In all of the pin-and-tube type heat exchanger and the micro channel type heat exchanger, a refrigerant flowing into the tube or flat tubes is heat-exchanged with an external fluid. Also, the fin may increase a heat exchange area between the refrigerant flowing into the tubes or flat tubes and the external fluid.
A heat exchanger may be used for an air conditioner as one part of a refrigerating cycle. Also, according to an operation mode of the air conditioner, the heat exchanger may serve as a condenser for condensing a refrigerant or an evaporator for evaporating the refrigerant. For example, when the heat exchanger serves as the condenser in a cooling operation of the air conditioner, the heat exchanger may serve as the evaporator in a heating operation.
Referring to FIG. 11, when a heat exchanger 1 serves as an evaporator, the micro channel type heat exchanger 1 according to the related art includes headers 2 and 3 coupled to a plurality of flat tubes 4. The headers 2 and 3 are provided in plurality. The first header 2 of the plurality of headers 2 and 3 is coupled to one side of the plurality of flat tubes 4, and the second header 3 is coupled to the other side of the plurality of flat tubes 4. Also, a heatsink fin 5 for easily heat-exchanging a refrigerant with external air is disposed between the plurality of flat tubes 4.
The first header 2 includes a refrigerant inflow part 6 through which the refrigerant is introduced into the heat exchanger 1 and a refrigerant discharge part 7 through which the refrigerant heat-exchanged within the heat exchanger 1 is discharged. The refrigerant inflow part 6 may be disposed on a lower portion of the first header 2, and the refrigerant discharge part 7 may be disposed on an upper portion of the first header 2.
Also, a baffle 8 for guiding a flow of the refrigerant is provided within the first and second headers 2 and 3. The baffle 8 is fixed within the first and second headers 2 and 3. The refrigerant within the first or second header 2 or 3 may be switched in flow direction by the baffle 8 to flow into the flat tubes 4.
The refrigerant introduced into the heat exchanger 1 may have a two-phase state. On the other hand, the refrigerant just before being discharged from the heat exchanger 1 may be a gaseous refrigerant or have a two-phase state having a very high dryness degree. That is, the refrigerant flowing into the flat tubes 4 may include a two-phase refrigerant in which a liquid refrigerant and a gaseous refrigerant are mixed with each other at a predetermined ratio.
When the two-phase refrigerant flows into the flat tubes 4, frictional resistance due to the refrigerant may occur in the flat tubes 4 to cause a pressure loss of the refrigerant. Also, when the pressure loss of the refrigerant occurs, heat exchange efficiency in the heat exchanger may be reduced.